package service

import (
	"encoding/json"
	"fmt"
	"log"
	"os"
	"path"

	"github.com/spf13/viper"
	"golang.org/x/crypto/bcrypt"
)

type UnauthorizedError string

func (uae UnauthorizedError) Error() string {
	return "Invalid user or password"
}

type UserConfig struct {
	DB *viper.Viper

	UserName string
	PassWord string
	Router   UserConfigRouter
	Others   []UserConfigOther
}

type UserConfigRouter struct {
	DNS string
	NFT UserConfigNFT
}

type UserConfigOther struct {
	DNS        string
	V6IID      string
	RegisterV4 bool
	NFT        UserConfigNFT
}

type UserConfigNFT struct {
	Table string
	Set4  string
	Set6  string
}

func LoadConfigForUser(username string, password string) (*UserConfig, error) {
	configFile := fmt.Sprintf("%s/%s.yml", C.Users.ConfigDir, username)
	configFile = path.Clean(configFile)
	log.Printf("Trying to load config file %s for user %s", configFile, username)

	if _, err := os.Stat(configFile); err != nil {
		log.Printf("cannot stat the file %s: %v", configFile, err)
		return nil, UnauthorizedError("cannot stat")
	}

	v := viper.New()
	v.SetConfigFile(configFile)
	err := v.ReadInConfig()

	if err != nil {
		return nil, fmt.Errorf("failed to parse config file %s: %v", configFile, err)
	}

	result := &UserConfig{DB: v}

	err = result.PasswordCheck(password)
	if err != nil {
		return nil, UnauthorizedError("pwcheck failed")
	}

	err = result.DB.Unmarshal(result)
	if err != nil {
		return nil, fmt.Errorf("failed to unmarshal config file %s: %v", configFile, err)
	}

	return result, nil
}

func HashPassword(pw []byte) (string, error) {
	hash, err := bcrypt.GenerateFromPassword(pw, bcrypt.DefaultCost)
	if err != nil {
		return "", fmt.Errorf("failed to create password hash: %v", err)
	}
	return string(hash), nil
}

func (ur *UserConfig) PasswordCheck(pwToCheck string) error {
	hashedPassword := []byte(ur.DB.GetString("password"))
	bytePwToCheck := []byte(pwToCheck)

	err := bcrypt.CompareHashAndPassword(hashedPassword, bytePwToCheck)

	return err
}

func (uc *UserConfig) PrettyPrint() string {
	s, err := json.MarshalIndent(uc, "", " ")
	if err != nil {
		log.Fatalf("Failed to pretty print UpdateConfig via JSON: %v", err)
	}
	return string(s)
}